| Squeaky Clean Eastbourne Limited | Administrative & support | 2003 |
| SRM (England) Ltd | Wholesale & retail | 2023 |
| SS Complete Solutions Limited | Information & communication | 2002 |
| ST Annes Lodge Eastbourne Limited | Households | 2005 |
| ST Michael's Hospice Lottery Limited | Arts & recreation | 1997 |
| ST Thomas a Beckett Nursery School Limited | Education | 1999 |
| ST. Annes Road Management Co. (Eastbourne) Ltd. | Households | 1996 |
| ST. Anthony's Centre | Other services | 2006 |
| STA Properties Limited | Real estate | 2002 |
| Stampbox Limited | Wholesale & retail | 2003 |
| Stanley Bloch Properties Limited | Construction | 1965 |
| Staplecroft Limited | Households | 1980 |
| Stapro Limited | Professional & scientific | 2000 |
| Startring Limited | Professional & scientific | 1989 |
| Station Close Rotherfield Management Company Limited | Professional & scientific | 1988 |
| Station Farm Glynde | | 1986 |
| Station House (Green Lane) Management Limited | Real estate | 2007 |
| Station Road Furniture Stores Limited | Wholesale & retail | 1935 |
| Statisfaction Statistical Consultancy Limited | Professional & scientific | 2002 |
| Steamtrain Limited | Administrative & support | 1996 |
| Steed Construction Limited | Construction | 1987 |
| Steepdale Limited | Households | 1991 |
| Steine Hair and Beauty Limited | Extraterritorial | 2006 |
| Step International | Wholesale & retail | 2008 |
| Stephen Wilson Partnership (Holdings) Limited | Professional & scientific | 2006 |
| Stepslot Property Management Limited | Households | 1989 |
| Steve Baldock Plumbing & Heating Ltd | Construction | 2004 |
| Steve Willis Training Ltd. | Other services | 1998 |
| Stevens & Billington Limited | Manufacturing | 1978 |
| Stimpson Direct Limited | Construction | 2000 |
| Stone Island Holdings Limited | Professional & scientific | 2000 |
| Stonehurst Construction Ltd | Construction | 2004 |
| Stonelodge Limited | Administrative & support | 1993 |
| Stones Accountancy (Sussex) Limited | Professional & scientific | 2007 |
| Storm Roofing Contractors Limited | Construction | 2002 |
| Stowe Commercial Estates Limited | Professional & scientific | 1988 |
| Stratum Resin Flooring Limited | Other services | 2004 |
| Studio Grant Harvey Limited | Administrative & support | 2018 |
| Studiogreenhouse Limited | Arts & recreation | 2004 |
| Style Photosetting Limited | Information & communication | 1979 |
| Stylee Mail Order Limited | Manufacturing | 2005 |
| Sugar International Limited | Professional & scientific | 2006 |
| Suncoast Church | Other services | 2005 |
| Sunningdale Management UK Limited | Information & communication | 1999 |
| Superior Dental Ceramics Limited | Health & social care | 2000 |
| Superoak Limited | Wholesale & retail | 2004 |
| Superquest I.T. Limited | Information & communication | 2004 |
| Supreme Care UK Ltd | Health & social care | 2000 |
| Surface Protection Systems (S.W.) Limited | Arts & recreation | 1988 |
| Surrey Select Limited | Real estate | 2010 |
| Susans Road House Services Limited | Real estate | 2005 |
| Sussex & Surrey Scaffolding Limited | Wholesale & retail | 1990 |
| Sussex Blinds (Brighton) Ltd | Construction | 1998 |
| Sussex Blinds and Shutters Limited | Extraterritorial | 2008 |
| Sussex County Arts Club | Other services | 2001 |
| Sussex Independent Financial Advisers Limited | Financial services | 2000 |
| Sussex Sheds Limited | Professional & scientific | 2005 |
| Sussex Trade Centres Limited | Wholesale & retail | 2001 |
| Swan Timber Limited | Manufacturing | 2007 |
| Sweet Talk Productions Limited | Information & communication | 2000 |
| Swynson Limited | Professional & scientific | 1999 |
| Symbiotic Technical Solutions Limited | Information & communication | 2013 |
| Symbol Computing Limited | Information & communication | 1996 |
| Synaptech.Org | | 1998 |
| Sync Catering Solutions Ltd | Manufacturing | 2026 |
| Synonym Limited | Information & communication | 1990 |
| Synthesys Strategic Consulting Limited | Professional & scientific | 2001 |
| Synthetic Rope Solutions Limited | Professional & scientific | 1996 |
| T & L Land Development Limited | Construction | 2006 |
| T Bourne & SON Limited | Transport & logistics | 1947 |
| T Stitt Plumbing & Heating Limited | Construction | 2004 |
| T W Keeley Limited | Manufacturing | 2007 |
| T. J. Wheeler Limited | Wholesale & retail | 1999 |
| T.A. Miles Construction Limited | | 1980 |
| T.V. Game Limited | Extraterritorial | 1986 |
| T.V. Pools Limited | Extraterritorial | 1985 |
| Tabatha White Limited | Hospitality | 2007 |
| Taboo (Eastbourne) Limited | Wholesale & retail | 2003 |
| Takapuna Bar Limited | Hospitality | 2002 |
| Talkbiznow Limited | Professional & scientific | 2007 |
| Talklink Limited | | 1989 |
| Tamworth House Management Limited | Administrative & support | 2006 |
| Tayfleet Limited | Households | 1996 |
| Taylor and Shroff Limited | Administrative & support | 2007 |
| Te-Elf Limited | Construction | 1978 |
| Team ZX1 Limited | Wholesale & retail | 1998 |
| Teamframes Limited | Wholesale & retail | 2002 |
| Techmedic Ltd | Information & communication | 2006 |
| Technalingua Limited | Information & communication | 2004 |
| Techno A.M. Ltd | Wholesale & retail | 2007 |
| Technopolis Limited | Professional & scientific | 1989 |
| Tektonic Limited | Information & communication | 2003 |
| Telephone Shop (Eastbourne) Limited(The) | Transport & logistics | 1986 |
| Telham Training Limited | Information & communication | 2004 |
| TEN Eaton Road Management Limited | Real estate | 1980 |
| Tenacity (RYE) Limited | Mining & quarrying | 2003 |
| Tenby Court Hove Limited | Households | 2004 |
| Tenterfield Investments Limited | Real estate | 2003 |
| Terinea Limited | Information & communication | 2001 |
| Termgreen Property Management Limited | Households | 1989 |